Acute Carotid Stent Thrombosis – What to do Now? Overview of Evidence on Risk Factors and Early Management Over the Last Two Decades

Abstract

Introduction - Acute carotid stent thrombosis (ACST) occurring in the first hours post-procedure is an exceedingly rare complication of carotid artery stenting but it is potentially devastating. The European Society for Vascular Surgery updated guidelines state thrombolysis and intravenous abciximab may be effective, but provide no specific recommendations. The aim of this review was to evaluate current literature on ACST, identifying all reported cases over the last two decades, with the final purpose of reporting on predictive factors and early management. Methods - A systematic review and meta-analysis was conducted according to the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Results - A total of 464 potentially relevant articles were initially selected. After reviewing records, at title or abstract level, a total of 29 articles with 60 patients were included. Twelve studies reported on ACST incidence rate in their cohorts ranging from 0.36% to as high as 33%. Considering aetiology, antiplatelet non-compliance/resistance, carotid artery dissection, plaque protrusion and long lesions needing two overlapping stents were the most reported. Emergency setting procedures seem associated with greater risk for ACST reaching as high as 5.6-33% incidence. Dual layer stents were associated with greater risk for ACST (45% Vs 3.7%; p=0.0001; OR=21.3). Use of a second overlapping stent as a bail out procedure due to dissection, malposition or long lesions was correlated with increased risk (7.3% Vs 0.002%). Long stenotic lesions (mm) and stent length (cm) were also risk factors (22.9±6.83 Vs 14.2±6.42; p=0.0034 and 3.8±0.4 Vs 2.8±0.86; p=0.0055 respectively). ACST was associated with neurologic status deterioration in 56.7%. Time to symptoms and/or ACST diagnosis had a median of 1.5 hours, with 30% occurring intra-procedural. Endovascular treatment was the most common approach to intraprocedural ACST: mechanical thrombectomy with or without concomitant facilitated thrombolysis (n=10) and stent-in-stent (n=2). Surgical options included carotid endarterectomy with stent explantation (n=9) and mechanical thrombectomy of embolus (n=1). Carotid endarterectomy was a bail-out after failed endovascular treatment in 2 cases. In asymptomatic ACST conservative management was rather unanimous. Conclusion - Incidence rate for ACST is greater in emergency settings, in neurologically unstable patients. Also, antiplatelet noncompliance, antiplatelet resistance, long stenotic lesions, use of more than one stent and dual layer stents are associated with increased risk. Decision on the best approach depends if ACST occurs intraprocedural or afterwards, on the development of neurologic status deterioration and on centre´s experience. Additional studies must be undertaken to better define optimal management.